The OI Genomics Core will be a resource that actively collaborates with project investigators by providing advanced and specialized methods in genotyping and high-throughput sequence analysis to assist in identifying new human genetic defects that cause recessive osteogenesis imperfecta. The Core will also provide capabilities to validate genes identified in the initial screen by analyzing segregation patterns of the mutations in the index families and sequence analysis in additional patients with OI phenotypes. The Cohn laboratory has had a longstanding working collaboration with all of the other members of the Program Project team, including specific studies of osteogenesis imperfecta. Because the methods to be used are well established within the laboratory and apply broadly to the proposed projects, consolidating the gene discovery methodologies in the Core (rather than each individual project) will provide both efficiency and cost savings.